Effects of protein-calorie malnutrition during suckling and post-weaning periods on discontinuous cranial traits in rats.

The influences of protein-calorie malnutrition (PCM), and sex during lactation and post-lactation on the frequencies of 25 discontinuous cranial traits (DCT), were investigated in Holtzman rats. Significant differences were observed in about 20% of the traits. Those traits were: the interfrontal fusion, the posterior incurvation of the palatine border, the double maxillary foramen, the double posterior palatine foramen, and the double frontal foramen. Total PCM was the nutritional factor which showed the greatest influence on the variability of the DCTs. It was followed, in decreasing order, by the PCM imposed during post-lactation and lactation. Sex had more influence than early PCM but less than late PCM. It is concluded that despite their apparent stability, a substantial number of DCTs were altered by both biological (like sex) and environmental factors (like nutritional deficiencies) imposed at different stages of postnatal development.